root / pobysoPythonSage / src / sageSLZ / sageRationalOperations.sage @ 79
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""" |
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Some small tools needed to manipulate lists of rational numbers |
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|
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AUTHORS: |
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|
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- Serge Torres: first operations set (2013-04) |
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""" |
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|
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def denominators(rationalList = None): |
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""" |
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Compute the list of the denominators of a rational numbers list. |
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""" |
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# No argument. |
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if rationalList is None: |
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raise TypeError('numerators takes a list of rationals.')
|
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try: |
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listLength = len(rationalList) |
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except Exception: |
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print "denominators:", rationalList, \ |
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"does not understand the len() function." |
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return([]) |
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if listLength == 0: |
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return([]) |
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if listLength == 1: |
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try: |
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return([QQ(rationalList[0]).denominator()]) |
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except Exception: |
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print "denominators:", rationalList[0], \ |
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"has no \"denominator()\" member." |
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return([]) |
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denominatorsList = [] |
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for i in xrange(listLength): |
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try: |
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denominatorsList.append(QQ(rationalList[i]).denominator()) |
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except Exception: |
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print "denominators:", rationalList[i], \ |
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"has no \"denominator()\" member." |
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return([]) |
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return(denominatorsList) |
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|
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def lcmm(rationalList = None): |
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""" |
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Compute the lcm of an sequence (list, tuple) of rational numbers. |
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""" |
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# No argument. |
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if rationalList is None: |
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raise TypeError('lcmm takes a list of rationals')
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# Try the len function. |
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try: |
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listLength = len(rationalList) |
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except Exception: |
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print "lcmm:", rationalList, "does not understand the len() function." |
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return(0) |
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# An empty list: return 0 |
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if listLength == 0: |
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return(0) |
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# Only one element, return it, wahtever it is. |
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if listLength == 1: |
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return(rationalList[0]) |
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try: |
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return(reduce(lcm, rationalList)) |
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except Exception: |
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print "Exception raised in lcmm!" |
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return(0) |
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|
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def numerators(rationalList = None): |
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""" |
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Compute the list of the numerators of a rational numbers list. |
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""" |
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# No argument. |
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if rationalList is None: |
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raise TypeError('numerators takes a list of rationals.')
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try: |
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listLength = len(rationalList) |
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except Exception: |
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print "numerators:", rationalList, \ |
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"does not understand the len() function." |
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return([]) |
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if listLength == 0: |
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return([]) |
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if listLength == 1: |
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try: |
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return(QQ(rationalList[0]).numerator()) |
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except Exception: |
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print "denominators:", rationalList[0], \ |
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"has no \"numerator()\" member." |
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return([]) |
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numeratorsList = [] |
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for i in xrange(listLength): |
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try: |
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numeratorsList.append(QQ(rationalList[i]).numerator()) |
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except Exception: |
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print "numerators:", rationalList[i], \ |
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"has no \"numerator()\" member." |
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return([]) |
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return(numeratorsList) |